The invention relates to a metal arc welding method, wherein a pulsating current is supplied to a consumable electrode.
In a prior art process of this kind, the so-called MIG-pulsed-arc process, adjustable voltage pulses are superimposed upon an adjustable fundamental voltage. These voltage pulses lead to a burn-off of the electrode and, at a suitable electrode feed rate, to a transfer of droplets to the workpiece through the arc. However, in this welding process, the adjustment of the electrode feed rate to the burn-off rate is extremely critical. If the electrode feed rate and burn-off rate are not properly chosen, shorts, spatter, pore formation, and lack of fusion will result, or a spray arc will be produced instead of the desired transfer of droplets to the workpiece through the arc. These disadvantages of lower quality are offset by the advantage that the method can be practiced at a higher welding speed.
If a high-quality weld joint is required, the so-called WIG process is employed. In this process, a constant current is supplied to the arc via a non-consumable electrode. The welding material is supplied separately. The disadvantage is that this process can only be implemented at a relatively low welding rate but this disadvantage is offset by the high welding quality.